Module testing (#1255)

Address issue #1254

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Henry Schreiner <HenrySchreinerIII@gmail.com>

tests/CMakeLists.txt

@@ -357,6 +357,24 @@ if(CLI11_INSTALL_PACKAGE_TESTS)
   set_property(TEST find-package-testsC PROPERTY LABELS Packaging)
   set_property(TEST find-package-testsC PROPERTY DEPENDS find-package-testsB)
 
+  if(CLI11_MODULE_TESTS)
+    add_test(
+      find-package-module
+      ${CMAKE_CTEST_COMMAND}
+      --build-and-test
+      "${CMAKE_CURRENT_SOURCE_DIR}/module_test"
+      "${CMAKE_CURRENT_BINARY_DIR}/module_test"
+      --build-generator
+      "Ninja"
+      --build-options
+      "-DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
+      "-DCMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}"
+      "-DCLI11_DIR=${CMAKE_INSTALL_PREFIX}"
+      ${package_test_command})
+
+    set_property(TEST find-package-module PROPERTY LABELS Packaging)
+  endif()
+
   if(NOT MSVC)
     # Tests for other CMake projects using the package_config files
     add_test(

tests/find_package_tests/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.14...4.1)
+cmake_minimum_required(VERSION 3.14...4.2)
 
 project(CLI11-find-package-test)
 

tests/module_test/CMakeLists.txt

@@ -0,0 +1,24 @@
+cmake_minimum_required(VERSION 3.14...4.2)
+
+project(CLI11-module-test)
+
+include(CTest)
+
+if(CLI11_DIR)
+  set(CMAKE_PREFIX_PATH ${CLI11_DIR})
+endif()
+
+set(CMAKE_CXX_STANDARD 23)
+# Test the CLI11 CMake package config
+find_package(CLI11 2.5 REQUIRED)
+
+# Test the target
+add_executable(module-test module_test.cpp)
+
+target_sources(module-test PUBLIC FILE_SET cmodule TYPE CXX_MODULES FILES cmodule.ixx)
+
+target_link_libraries(module-test CLI11::CLI11)
+target_compile_options(module-test PUBLIC -fmodules-ts)
+
+add_test(NAME module-test1 COMMAND module-test one)
+set_property(TEST module-test1 PROPERTY PASS_REGULAR_EXPRESSION "OK: export module")

tests/module_test/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2024 scivision
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

tests/module_test/cmodule.ixx

@@ -0,0 +1,20 @@
+// Copyright (c) 2024 scivision
+// Copyright (c) 2025 University of Cincinnati, developed by Henry Schreiner
+// under NSF AWARD 1414736 and by the respective contributors.
+// All rights reserved.
+//
+// SPDX-License-Identifier: MIT
+
+// modified from https://github.com/iTrooz/CppModules/blob/cli11 for use in CLI11 tests
+
+module;
+
+#include <CLI/CLI.hpp>
+
+export module cmodule;
+
+export void foo(CLI::App *app) {}
+
+export int add(int a, int b) { return a + b; }
+
+export int subtract(int a, int b) { return a - b; }

tests/module_test/module_test.cpp

@@ -0,0 +1,30 @@
+// Copyright (c) 2024 scivision
+// Copyright (c) 2025 University of Cincinnati, developed by Henry Schreiner
+// under NSF AWARD 1414736 and by the respective contributors.
+// All rights reserved.
+//
+// SPDX-License-Identifier: MIT
+
+// modified from https://github.com/iTrooz/CppModules/blob/cli11 for use in CLI11 tests
+
+#include <cassert>
+#include <cstdio>
+#include <cstdlib>
+
+import cmodule;
+
+int main() {
+    int a = 1;
+    int b = 2;
+
+    int absum = add(a, b);
+    int abdif = subtract(a, b);
+
+    assert(a + b == absum);
+    assert(a - b == abdif);
+
+    // used this instead of <iostream> to work with older compilers that may choke on <iostream> implicit includes
+    printf("OK: export module\n");
+
+    return EXIT_SUCCESS;
+}

tests/package_config_tests/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.14...4.1)
+cmake_minimum_required(VERSION 3.14...4.2)
 
 project(CLI11-package-config-test)